Partial ethers of cellulose and d, l-butadiene dioxide



United States Patent 3,150,920 PARTIAL ETHERS 0F CELLULOSE AND d,l-illJTADlElJE Bli-QXEBE Ralph .l. Berni, .lohn B. Mcllelvey, and 'tuth R. Eenerito, New @rlcans, La, assignors to the United States of America as represented by the Secretary of Agriculture No Brawing. Filed Dec. 12, 1962, Ser. No. 244,224 ll (Cl. 8-420) (Granted under Title 35, US. Code (1952), sec. 266) A nonexclusive, irrevocable, royalty free license in the invention herein described, for all governmental purposes throughout the world with the power to grant sublicenses for such purposes is hereby granted to the government of the United States of America.

This invention relates to cellulose ethers. More particularly, this invention relates to the production of 2,3 dihydroxybutyl-l,4 diethers of cellulose.

A primary object of the present invention is to provide a process for treating cotton cellulose and cotton cellulose derivatives with d,l-butadiene dioxide dissolved in carbon tetrachloride after a pretreatment with alkaline solutions such as aqueous sodium, lithium, potassium, and tetrabutylammonium hydroxides. This process produces fabrics which are crosslinked, have improved Wet and dry crease recovery, and retain after treatment all the desirable textile properties of the untreated fibers.

A further object of this invention is to provide a process of modifying the properties of cellulosic textiles that contain hydroxyl groups, to impart or enhance properties such as dimensional stability and luster.

The application of cellulose etherifying agents by the use of a three phase system (CCl H 0, and NaOH) is known in the prior art as well as the use of mesobutadiene dioxide to obtain dry and Wet crease recovery. However, novelty is claimed since wet and dry crease recovery can be obtained with d,l-butadiene dioxide with high concentrations of base as pretreatments requiring only short and more practicable reaction times (40 minutes to 1 hour). Previously, reaction times of 8 to 24 hours were required with the meso isomer of butadiene dioxide.

The three phase system is a necessity for reaction of cellulose and d,l-butadiene dioxide, since the usual pad, dry cure method fails, due to the fast rate of hydrolysis of the epoxide groups in intimate aqueous base solutions. d,l-Butadiene dioxide can be successfully reacted with cellulose pretreated with high base concentrations (6% to 23 inclusive) because it is soluble at the higher concentrations, which allows it to be distributed in the water layer near the reactive cellulose hydroxyls. Since the distribution is a relatively slow process the butadiene dioxide distributes itself in the water layer at a rate which causes a high percentage of the epoxide groups to react with cellulose hydroxyls in the NaOH-water layer. Meso-butadiene dioxide could be used in the process as long as low base concentrations less than 6% were used, since it had some solubility at low concentrations of aqueous base. However, this necessitated longer reaction times, since the rate of the butadiene dioxidecellulose reaction depends partially on the base concen tration. This process we have discovered imparts both wet and dry crease resistance to the cotton cellulosic fabrics, and improves luster and dimensional stability, without altering significantly the strength, color, hand, and fibrous character of the cellulosic material.

In general, in accordance with the present invention, a hydroxyl group containing cellulosic material is partially etherified by reaction with an etherifying agent (d,l-butadiene dioxide) dissolved in carbon tetrachloride after pretreatment with aqueous solutions of sodium, lithium, potassium, or tetrabutylammonium hydroxide.

3,150,920 Patented Sept. 29, 1964 The process of the present invention is characterized by a critical sequence of pretreatments of the cellulosic materials with aqueous sodium hydroxide solutions or other aforementioned alkaline solutions, followed by immersion of the pretreated materials in d,l-butadie:ne dioxide dissolved in carbon tetrachloride, and finally Washing the etherified cellulosic material. The sequence of operations is described in detail in the operating examples below.

Substantially, any cellulosic material containing free hydroxyl groups can be employed in the present processes. Illustrative examples of such materials include cellulose derived from cotton, flax, ramie, and the like vegetable materials; wood cellulose, regenerated cellulose, such as viscose rayon and the like; partial esters of cellulose, such as partially acetylated cellulose; beta-propiolactone reacted cellulose and the like; partial ethers of cellulose, such as partially cyanoethylated, partially aminoethylated, and partially carboxymethylated cellulose. In general, we prefer as starting materials cellulosic textile fabrics, chemically modified or not modified, wherein the original fibrous character of the material has been retained.

In reacting the cellulosic material with the etherifying agent (d,l-butadiene dioxide) substantially any apparatus usually employed in the etherification of cellulosic fabrics can be employed. In carrying out the process the cellulosic material to be reacted is first padded twice With aqueous solutions of sodium hydroxide (2. to 23%, inclusive), or other aforementioned hydroxides, to approximately wet pickup, and then the fabrics are rolled loosely to fit in graduated cylinders. The fabrics are immersed completely in 20% solution (by volume), of d,lbutadiene dioxide in carbon tetrachloride. (Solutions of as low as 5% by volume may be employed, but 20% concentration is preferred.) The fabrics can be reacted for varying periods of time, depending on the base concentration used in pretreatment. For 15% base pretreatments a period of time of 40 minutes was necessary in order to impart improved dry and wet crease recovery to the fabrics.

The extent of reaction can be varied widely, and is commonly expressed as degree of substitution, or simply D.S. A D8. of 3, which is a maximum figure, would indicate the replacement of each of the hydrogen atoms of the 3 reactive hydroxyl groups of the anhydroglucose (the basic unit in cellulose) with a 2,3-dihydroxybutyl group, while the replacement of only one of these hydrogen atoms would be referred to as a D8. of 1.

The degree of substitution can be varied by varying time and/ or concentration of the hydroxyl ion in the pretreatment. Although room temperatures (20 to 25 C.) are preferred temperatures from 0 to 60 C. can be employed in this process. Our preferred conditions for etherification to impart improved dry and wet crease recovery, improved dimensional stability, and improved luster to fabrics constitute the pretreatment of said fabrics with 23% NaOH, and subsequently reacting with d,lbutadiene dioxide for as short as 10 minutes; or the pretreatment with 15% NaOH and subsequently reacting with d,l-butadiene dioxide for as short as 40 minutes. The dry and wet crease recovery, dimensional stability, and luster are achieved at very low D.S., i.e., 0.20 to 0.77.

Following etherification the fabric being treated is removed from the reaction medium, and Washed free of reactant solution, using tap water, and weak acid for removal of the alkaline ingredients. The washing procedure includes quenching of the reaction mixture from the treated cellulose fabric for about 3 to 5 minutes with running tap water at temperature of 25 to 30 C.; glacial acetic acid or dilute nitric acid is then added to wash solution to neutralize base which might be in excess; then more tap Water is used for removal of excess acid.

The Washed, partially etherified cellulosic material can be dried, using substantially any of the procedures conventionally employed for the drying of cellulosic materials. It is preferable to conduct the drying at relatively 'low' temperatures, say below 110 C. p

The following examples are illustrative of the details of this invention. The d,l-butadiene dioxide used in the examples was a commercial product with a B.P. of 145 C. The carbon tetrachloride was likewise a commercial product; as were the hydroxides employed in pretreatmerits.

Example 1 An 80 x 80 cotton fabric sample (approximately 10.0

grams) was padded twice with 15% aqueous NaOH to approximately 100% Wet pickup, and thereafter completely immersed in 100 ml. graduated cylinder containing 20% by volume of d,l-butadiene dioxide in carbon tetrachloride solution. The fabric was reacted for 35 minutes at room temperature (25 C.). The fabric was then removed, and the reaction quenched with tap water for a period of about 10 minutes. The fabric sample after quenching was soaked in a mild acid bath for about minutes, and was finally washed free from acid with water.

Subsequent to washing, the fabric was ironed dry and moisture equilibrated overnight. The weight gain was 7.0%, and the dry and wet crease angles (warp and fill) were 231 and 302, respectively. All crease angles mentioned are Monsanto (warp-l-fill) degrees.

Examples 2-5 The procedure according to Example 1, except for changes listed in the following table:

Crease Angles (W+F) Reaction Time Weight Gain (Minutes) (Percent) Dry Wet *15% NaOH replaced by NaOH.

Example 6 (This example shows that base concentration as low as 2% can be used to give required results however longer reaction times are needed.)

The procedure according to Example 1, except for the use of 2% NaOH in place of NaOH, and a reaction time of 7 hours. The treated fabric had a weight gain of 7.8%, and dry and Wet crease angles of 227 and 248, respectively.

Example 7 (This example shows that other bases may be used instead of NaOH.)

The procedure according to Example 1, except for replacement of 15% NaOH with 6% LiOH, and reaction time of 50 minutes. The treated fabric had a weight gain of 6.2%, and dry and wet crease angles of 258 and 224, respectively.

Example 8 The procedure according to Example 1, except for replacement of d,l-butadiene dioxide with mesa-butadiene dioxide, and reaction times of 4 and 0.25 hour, respectively. The treated fabrics had weight gains of 37.9% and 3.7%, and dry crease angles of 183 and 122, with wet crease angles of 334 and 166, respectively.

We claim:

1. A process comprising treating a cellulosic material containing free hydroxyl groups with an aqueous solution of a base selected from the group consisting of NaOl-I, KOH, LiGI-I, and tetrabutyl ammonium hydroxide, reacting the thus-treated cellulosic material with d,l-butadiene dioxide dissolved in carbon tetrachloride until a degree of substitution of about from 0.20 to 0.77 is achieved, washing the resulting cellulosic material to remove unreacted reagents, and drying the washed cellulosic material.

2. The process of claim 1 wherein the aqueous solution of the base contains about from 2 to 23 weight percent of the base.

3. The process of claim 1 wherein the aqueous solution of the base contains about from 6 to 23 weight percent of the base.

4. A process comprising padding a cellulosic material containing free hydroxyl groups with an aqueous solution containing about from 2 to 23 weight percent of a base selected from the group consisting of NaOH, KOH, LiOH, and tetrabutyl ammonium hydroxide, reacting the padded cellulosic material with about from 5 to 20 volumes percent of d,l-butadiene dioxide dissolved in carbon tetrachloride at a temperature of about from 0 to 60 C. until a degree of substitution of about from 0.20 to 0.77 is achieved, washing the resulting cellulosic material to remove unreacted reagents, and drying the washed cellulosic material.

5. A process comprising padding a cellulosic material containing free hydroxyl groups with an aqueous solution containing about from 6 to 23 weight percent of a base selected from the group consisting of NaOH, KOH, and LiOH to a weight pickup of about percent, reacting the padded cellulosic material with about 20 volume percent of d,l-butadiene dioxide dissolved in carbon tetrachloride at room temperature for about from 10 minutes to one hour to'achieve a degree of substitution of about from 0.20 to 0.77, washing the resulting cellulosic'rnaterial to 7 remove unreacted reagents, and drying the washed cellulosic material.

6. The process of claim 5 wherein the cellulosic material containing free hydroxyl groups is a cellulosic textile fabric in which the original fibrous character has been retained.

7. The process of claim 5 wherein the base is NaOH.

8. The process of claim 5 wherein the base is KOH.

9. The process of claim 5 wherein the base is LiQI-l.

10. The process of claim 5 wherein the bees is NaOH, the aqueous solution thereof contains about 23 weight percent NaOH, and the time of reaction with the d,l-butadiene dioxide is about 10 minutes.

11. The process of claim 5 wherein the base is NaOH, the aqueous solution thereof contains about 15 weight percent NaOH, and the time of reaction with the d,l-butadiene dioxide is about 40 minutes.

References Cited in the file of this patent McKelvey et al.: Journal of Polymer Science, vol. 51, pages 209-230 (1960).

Benerito et al.: Textile Research Journal, vol. 31, No. 9, September 1961, pp. 757769.

Reinhardt: Textile Research Journal, vol. 31, No. 11, November 1961, pp. 941-950.

McKelvey et al.: Textile Research Journal, vol. 29, November 1959, pp. 918-925, 260-231. 

1. A PROCESS COMPRISING TREATING A CELLULOSIC MATERIAL CONTAINING FREE HYDROXYL GROUPS WITH AN AQUEOUS SOLUTION OF A BASE SELECTED FROM THE GROUP CONSISTING OF NAOH, KOH, LIOH, AND TETRABUTYL AMMONIUM HYDROXIDE, REACTING THE THUS-TREATED CELLULOSIC MATERIAL WITH D,1-BUTADIENE DIOXIDE DISSOLVED IN CARBON TETRACHLORIDE UNTIL A DEGREE OF SUBSITUTION OF ABOUT FROM 0.20 TO 0.77 IS ACHIEVED, WASHING THE RESULTING CELLULOSIC MATERIAL TO REMOVE UNREACTED REAGENTS, AND DRYING THE WASHED CELLULOSIC MATERIAL. 